CnC_Remastered_Collection

Command and Conquer: Red Alert
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PK.H (4427B)

      1 //
      2 // Copyright 2020 Electronic Arts Inc.
      3 //
      4 // TiberianDawn.DLL and RedAlert.dll and corresponding source code is free 
      5 // software: you can redistribute it and/or modify it under the terms of 
      6 // the GNU General Public License as published by the Free Software Foundation, 
      7 // either version 3 of the License, or (at your option) any later version.
      8 
      9 // TiberianDawn.DLL and RedAlert.dll and corresponding source code is distributed 
     10 // in the hope that it will be useful, but with permitted additional restrictions 
     11 // under Section 7 of the GPL. See the GNU General Public License in LICENSE.TXT 
     12 // distributed with this program. You should have received a copy of the 
     13 // GNU General Public License along with permitted additional restrictions 
     14 // with this program. If not, see https://github.com/electronicarts/CnC_Remastered_Collection
     15 
     16 /* $Header: /CounterStrike/PK.H 1     3/03/97 10:25a Joe_bostic $ */
     17 /***********************************************************************************************
     18  ***              C O N F I D E N T I A L  ---  W E S T W O O D  S T U D I O S               ***
     19  ***********************************************************************************************
     20  *                                                                                             *
     21  *                 Project Name : Command & Conquer                                            *
     22  *                                                                                             *
     23  *                    File Name : PK.H                                                         *
     24  *                                                                                             *
     25  *                   Programmer : Joe L. Bostic                                                *
     26  *                                                                                             *
     27  *                   Start Date : 07/03/96                                                     *
     28  *                                                                                             *
     29  *                  Last Update : July 3, 1996 [JLB]                                           *
     30  *                                                                                             *
     31  *---------------------------------------------------------------------------------------------*
     32  * Functions:                                                                                  *
     33  * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     34 
     35 #ifndef PK_H
     36 #define PK_H
     37 
     38 #include	"int.h"
     39 
     40 /*
     41 **	This class holds a public or private key used in Public Key Cryptography. It also serves
     42 **	as the conduit for encrypting/decrypting data using that key. Cryptography, using this
     43 **	method, has a couple of characteristics that affect how it is used. One, the process of
     44 **	encrypting/decrypting is very slow. This limits the effective quantity of data that can
     45 **	be processed. Two, the ciphertext is larger than the plaintext. This property generally
     46 **	limits its use to streaming data as opposed to random access data. The data is processed
     47 **	in blocks. The size of the ciphertext and plaintext blocks can be determined only from
     48 **	the key itself.
     49 **
     50 **	A reasonable use of this technology would be to encrypt only critical data such as the
     51 **	password for a fast general purpose cryptographic algorithm.
     52 */
     53 class PKey
     54 {
     55 	public:
     56 		PKey(void) : Modulus(0), Exponent(0), BitPrecision(0) {}
     57 		PKey(void const * exponent, void const * modulus);		// DER initialization.
     58 
     59 		int Encrypt(void const * source, int slen, void * dest) const;
     60 		int Decrypt(void const * source, int slen, void * dest) const;
     61 
     62 		static void Generate(Straw & random, int bits, PKey & fastkey, PKey & slowkey);
     63 
     64 		int Plain_Block_Size(void) const {return((BitPrecision-1)/8);}
     65 		int Crypt_Block_Size(void) const {return(Plain_Block_Size()+1);}
     66 		int Block_Count(int plaintext_length) const {return((((plaintext_length-1)/Plain_Block_Size())+1));}
     67 
     68 		int Encode_Modulus(void * buffer) const;
     69 		int Encode_Exponent(void * buffer) const;
     70 
     71 		void Decode_Modulus(void * buffer);
     72 		void Decode_Exponent(void * buffer);
     73 
     74 		static long Fast_Exponent(void) {return(65537L);}
     75 
     76 	private:
     77 
     78 		// p*q
     79 		BigInt Modulus;
     80 
     81 		// 65537 or
     82 		// inverse of (p-1)(q-1).
     83 		BigInt Exponent;
     84 
     85 		// Maximum bits allowed for block.
     86 		int BitPrecision;
     87 };
     88 
     89 
     90 #endif